<?xml version="1.0"?>
<svg width="10cm" height="5cm" viewBox="0 0 1000 500"
     xmlns="http://www.w3.org/2000/svg"
	 version="1.1">

  <script>
  function init()
  {
    document.getElementsByTagName("rect")[0].style.display = "-moz-inline-stack";
  }
  
  window.addEventListener("load", init, false);
  </script>
  
  <rect requiredFeatures="http://www.w3.org/TR/SVG11/feature#SVG-nonexistent-feature"/>
</svg>
